Electropneumatic brake.



W. V. TURNER.

ELECTROPNEUMATIC BRAKE.

APPLICATION FILED ocms, 1914.

1,174, 105. Patented Mar. 7, 1916. v

w wgz INVENTOR WITNESSES T COLUMBIA PLANOGRAPH 0, WASHINGTON, n. c.

UNITED STATES: PATE T cr mes. 1

WALTER V. TURNER, 0F EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THE WESTING-HOUSE AIR BRAKE COMPANY, OF VTILMERDING, PENNSYLVANIA, A GORPORATION OFPENNSYLVANIA.

ELECTROPNEUMATIC BRAKE.

Specification of Letters Patent. I I Patented Mar, '7, 1916,

Application filed October 6, 1914. Serial No. 865,254.

To all whom it may concern Be it known that I, WALTER V. TURNER, acitizen of the United States, residing at Edgewood, in the county ofAllegheny and State of Pennsylvania, have invented new and usefulImprovements in Electropneumatic Brakes, of which the following is aspecification. V

This invention relates to fluid pressure brakes, and more particularlyto a brake of the electro-pneumatic type. V

In the automatic fluid pressure brake, an excessive rate of reduction inbrake pipe pressure in service applications is prevented by theemployment of the so-called equalizing discharge valve device, evenwhere there is leakage from the brake pipe.

In the case of the electro-pneumatic brake, where an electricapplication is eiiectedby venting fluid from the brake plpe through theoperation of a magnet valve, a similar excessive reduction in brake pipepressure may be produced, particularly in connection with brake pipeleakage, which is liable to cause an undesired emergency application ofthe brakes.

The principal object of my invention 1s to provide means for limitingthe rate of reduction in brake pipe pressure when the brakes areelectro-pneumatically applied.

In the accompanying drawing; Figure 1 illustrates an electro-pneumaticbrake apparatus with my improvement embodied therein, showing the partsin application posi tion; Fig. 2 a fragmentary sectional view of theequalizing valve device with the parts in normal release position; andFig. 3 a similar view, showing the parts in over reduction position.

As shown in the drawing, the construction may comprise a casing 1 havinga piston chamber 2 containing an equalizing piston 3 and connected tobrake pipe 4, and having a valve chamber 5 containing a main slide valve6 and a graduating valve 7 mounted on and having a movement relative tothe main slide valve, the valve chamber 5 being I connected by pipe 8 tothe usual auxiliary fluid from the brake pipe through passage 12 topassage 13 which leads to the seat of the main valve 6.

In the release position of the main slide valve 6, as shown in Fig. 2 ofthe drawing, passage 13 is connected by cavity 14 with exhaust port 15so that when the magnet 10 is energized on each car of the train toeffect an application of the brakes,-the valve 11 is opened andestablishes communication from the brake pipe through passages 12 and 13and cavity 14 to exhaust port 15f Fluid under pressure is thereuponvented from the brake pipe and the equalizing piston 3 is moved out toapplication position, as shown in Fig. 1 of the drawing. In thisposition, the cavity 14 still maintains communication between thepassage 13 and the exhaust port 15, while 1 service port 16, which wasuncovered by the preliminary movement of the graduating slide valve 7,is brought into register with brake cylinder port 17. Fluid underpressure is now supplied from the auxiliary reservoir 9 to the brakecylinder in the usual manner, and if the magnet valve 11 is closed, thereduction in brake pipe pressure ceases, and as soon as the auxiliaryreservoir pressure substantially equalizes with the reduced brake pipepressure, the graduating valve 7 is moved back by the piston 3 intheusual manner, closingtheservice port 16. If the magnet valve 11 is leftopen andthere should be brakepipe leakage such that the total rate ofreduction in brake pipe pressure exceeds the rate at which the auxiliaryreservoir pressure is reduced by flow to the brake cylinder, then theequalizing piston will move out beyond service application position topartially or totally out off communication from the passage 13 to theexhaust port 15, as shown in Fig. 3 of the drawing. During thismovement, it will be noted that a foot extension 18 of the service port16 maintains communication with brake cylinder port 17, so that fluidcontinues to flow from the auxiliary reservoir to the brake cylinderuntil the auxiliary reservoir pressure becomes slightly less than thereduced brake pipe pressure, when the piston 3 will move the graduatingvalve back, so that cavity 19 therein connects a port 20 leading fromcavity 14 with a port 21 which registers with passage 13. Since cavity14 is still in register with exhaust port 15, it will be seen that com-'munication is now open so that fluid can be again vented from the brakepipe, if the any tendency of the brake pipe pressure re magnet valve 11is still open. If there is ducing faster than the predetermined rate,the piston 3 will move the graduating valve 7 and thus automaticallyrestrict the passage 21 until the rate of reduction in brake pipepressure corresponds with the rate of reduction in auxiliary reservoirpressure by flow to the brake cylinder.

Having now described my invention, what I claim as new and desiretosecure by Letters Patent, is:

1. In an electro-pneuma-tic brake, the combination with a brake pipe andan equalizing valve device operated upon a reduction in brake pipepressure for effecting an application of the brakes, of electricallycontrolled means for venting fluid from the brake pipe through acommunication controlled by said equalizing valve device.

2. In an electro-pneumatic brake, the combination with a brake pipe andan equaliz ing valve device operated upon a reduction in brake pipepressure for effecting an application of the brakes, of an electricallycontrolled valve for venting fluid from the brake pipe through portscontrolled by said valve device, communication through said ports beingopen during the movement of the valve device to service applicationposition and adapted to be closed upon further movement.

3. In an electro-pneumatic brake, the combination with a brake pipe, amain valve and an auxiliary valve for controlling the admission of fluidto the brake cylinder, and a piston subject to brake pipe pressure foroperating said valves, of an electrically controlled valve for ventingfluid from the brake pipe through a cavity in the main valve under aservice rate of reduction in brake pipe pressure and ports controlled bythe auxiliary valve through which the venting of fluid from the brakepipe is controlled when the brake pipe pressure is reduced at a greaterrate.

4. In an electro-pneumatic brake, the combination with a brake pipe anda triple valve device operated by a reduction in brake pipe pressure foreffecting an application of. the brakes, of electrically controlledmeans for venting fluid from the brake pipe through a communicationcontrolled by said valve device, movement of said valve device beyondservice application position being adapted to close said communication.

5. In an electro-pneumatic brake, the combination with a brake pipe anda triple valve device comprising a main valve, an auxiliary valve havinga movement relative to the main valve, and a piston subject to brakepipe pressure for operating said valves, of an electrically controlledvalve for venting fluid from the brake pipe through a communicationcontrolled by said triple valve device, the main valve thereof beingadapted to close said communication upon movement beyond serviceposition and the auxiliary valve being adapted to then control saidcommunication.

In testimony whereof I'have hereunto set my hand.

WALTER V. TURNER. lVitnesses:

A. M. CLEMENTS, S. W. Knnrnn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

